The first I.S. machine was patented in U.S. Pat. Nos. 1,843,159, dated Feb. 2, 1932, and 1,911,119, dated May 23, 1933. Today more than 4000 I.S. machines, manufactured by a number of companies, are in use worldwide, producing more than a billion bottles every day of the year. An I.S. (individual section) machine has a plurality of identical sections (a section frame in which and on which are mounted a number of section mechanisms) each of which has a blank station which receives one or more gobs of molten glass and forms them into parisons having a threaded opening at the bottom (the finish) and a blow station which receives the parisons and forms them into bottles standing upright with the finish at the top. An invert and neck ring holder mechanism which includes an opposed pair of arms, rotatable about an invert axis, carries the parisons from the blank station to the blow station inverting the parisons from a finish down to a finish up orientation in the process. A bottle formed at the blow station is removed from the section by a take out mechanism.
The blank station includes opposed pairs of blankmolds and the blow station includes opposed pairs of blowmolds. These molds are displaceable be tween open (separated) and closed positions. Opposed pairs of neck ring molds, carried (supported proximate their tops) by the invert and neck ring holder mechanism, define the finish of the bottle and hold a formed parison as it is transferred from the blank station to the blow station.
The length of a parison generally corresponds to the length of a formed bottle and hence the height of the blankmolds may have a wide variety of heights. The blankmolds are conventionally hung, proximate their tops, from suitable carriers such as disclosed in U.S. Pat. Nos. 5,516,352 and 4,878,935 which try to locate the bottle centrally relative to the axis of the invert and neck ring holder mechanism, whereby the finish of the formed parison will be within a wide range of vertical positions. The vertical location of the neck ring arms accordingly will be changed to follow the finish location and to facilitate this change, quick change neck ring arms have been developed (U.S. Pat. No. 4,652,291).
Since the closed neck rings lie proximate the top of the tooling of a plunger mechanism (either a press and blow plunger or a blow and blow plunger) such as disclosed in U.S. Pat. Nos. 4,272,273, 3,314,775, and 3,190,188, the plunger mechanism will be relocated vertically to follow the neck rings. To this end, since the introduction of the I.S. machine more than 50 years ago, the plunger mechanism, which defines a small hole in the parison at the finish end, has been mounted on a jack screw which is secured to the bottom wall of the section frame. The jack screw can be rotated to raise and lower the plunger mechanism to follow the vertical relocation of the neck ring holders. A conventional plunger mechanism has a vertical stroke (a positioning range) of as much as 8". The plunger mechanism is vertically displaceable relative to a guide ring which is secured to the top wall of the section frame and guides the vertical movement of the plunger mechanism. As a result, any attempt to change the position of the plungers of the plunger mechanism, by displacing the guide ring, to establish alignment between the plunger of the plunger mechanism and the axis of the mold, will tilt the plunger mechanism relative to the fixed base and this is very undesirable. Furthermore, to convert the section from single gob operation to double gob operation or to switch from double gob operation at one spacing to double gob operation at a different spacing, for example, the entire plunger mechanism above the jack screw must be changed. This is made even more difficult since all service air lines (as well as all lubrication lines) which connect to the plunger mechanism via individual hoses, must be individually disconnected and reconnected, and, where the configuration of the machine is changed from double gob operation to triple gob operation, for example, new lines have to be defined. Additionally, since the molds are hung from structure proximate their top, growth due to heat occurs downwardly towards the plunger mechanism and may require repositioning of the neck ring holders and plunger mechanism.